Automatic self-releasing adjustable torque wrench



Feb. 3, 1959 M. A. BARKER ET AL 2,872,004

AUTOMATIC SELF-RELEASING ADJUSTABLE TORQUE WRENCH Filed May 13, 1955 2Sheets-Sheet 1 Fig./

Melvin Allen Bar/rr 'T Arthur J. Rooks 50 INVENTORS WWW; Em

AUTOMATIC SELF-RELEASING ADJUSTABLE] TORQUE WRENCH Feb. 3, 1959 M. A.BARKER ET AL 2 Sheets-Sheet 2' Filed May 13, 1955 Melvin Allen BarkerArthur .1. Racks INVENTORS 0 BY QdW FM L torque wrenches so as to UnitedStates Patent O AUTQMATI'C SELF-RELEASING ADJUSTABL TORQUE WREN CHMelvin Allen Barker, Livonia, and Arthur J. Rooks,

Birmingham, Mich.

Application May 13, 1955, Serial No. 508,086

1 Claim. (Cl. 192-56) This invention relates to new and usefulimprovements in wrenches, and more specifically to an improved automaticadjustable torque wrench which is of the selfreleasing type.

This invention is an improvement over our automatic adjustable torquewrench as disclosed in our Patent No. 2,527,517, issued October 31,1950.

In our prior torque wrench, we set forth a novel clutch arrangementwhich was extremely simple and at the same adjustable so that the wrenchcould be set for various torques. However, the clutch was so constructedwhereby once the wrench was removed from a nut or bolt and therestraining force of the nut or bolt removed from the socket end of thewrench, then the socket began to turn again with the result that themotor driving the wrench would have to be stopped before the wrenchcould be engaged on another bolt or nut. It is therefore the primaryobject of this invention toprovide an improved automatic adjustabletorque wrench which is of the self-releasing type and which will stoprotating upon the application of the desired torque on a nut or bolt.

Another object of this invention is to provide an improved torque wrenchwhich includes a first clutch assembly for connecting together halves ofthe torque; wrench whereby the halves may be separated upon theapplication of a predetermined torque to limit the torque. applied tonuts and bolts, and a second clutch which is operative to render thefirst clutch ineffective whereby a socket portion of a torque wrenchwill stop rotating when the desired torque is applied to a nut or bolt,and will not again operate until reapplied to another nut or bolt.

A further object of this invention is to provide an improved cam typeclutch for use in adjustable torque wrenches, the cam type clutch beingof such .a nature whereby it may be readily applied to existing types ofmake them self-releasing.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing bad to the accompanying drawings forming a part hereof. whereinlike numerals refer to like parts throughout, and in which:

Figure l is an elevational view of the improved torque wrench and showsthe general appearance thereof, a por tion of the shank thereof beingomitted;

Figure 2 is a longitudinal vertical sectional view taken through thecenter of the torque wrench of Figure l and shows the details of thevarious components thereof;

Figure 3 is a transverse horizontal sectional view taken substantiallyupon the plane indicated by the section line 3-3 of Figure 2 and showsthe connection between the two bodies which form the housing portion ofthe wrench and the connection between one of the bodies and a drivemember of the cam type clutch assembly;

Figure 4 is a horizontal sectional view taken substantially upon theplane indicated by the section line 4-4 ,upper part .44 which seats onthe downward movement of the shank portion 42 through Patented Feb. 3,1959 type clutch;

Figure 5 is an enlarged perspective view of a member incorporating atthe upper end thereof one-half of the cam type clutch;

Figure 6 is an enlarged perspective view of a male clutch member of theslip type clutch;

Figure 7 is an enlarged perspective view showing the undersideconfiguration of an annular member removably securable to the upper endof the male clutch member of Figure 6, the annular member incorporatingone-half of the cam type clutch;

Figure 8 is an elevational view of the upper body with portions thereofshown in section in order to clearly illustrate the details thereof; and

Figure 9 is a vertical sectional view taken through the female clutchmember of the slip type clutch and shows the general details thereofwith the male clutch member and a shank normally carried therebyremoved. v

Referring now to the drawings in detail, it will be seen that the torquewrench includes an upper body 10 which is provided at the upper endthereof'with an internally threaded bore 12 in which is threadedlyengaged a threaded lower end 14 of a shank 16.

The upper body 10 is hollow to form a chamber 18 and is telescopedwithin a hollow lower body 20, there being provided in the lower body 20a chamber 22. In order that the upper body 10 and the lower body 20 maybe adjustably connected together to form a housing, which is referred toin general by the reference numeral 24, of a predetermined adjustedlength, the upper portion of the lower body 20 is internally threaded,as at 26, and has threadedly engaged therewith external threads 28formed in the lower portion of the upper body 10.

In order that the bodies 1d and 20 may be retained in selected adjustedposition with respect to each other, there is formed in an intermediateportion of the lower body 20 an internally threaded bore 30 whichextends radially therethrough. Threadedly engaged in the bore 30 is asetscrew 32. The exterior of the upper body 10 in the vicinity of thethreads 28 is provided witha plurality of vertical slots 34, as is bestillustrated in Figure 3, for selectively receiving the setscrew 32. Inthis manner, the bodies 10 and 20 are locked againstrotation.

The lower body 20 is provided-with a bottom wall 36 having a relativelylarge bore 33 therethrough, the bore 38 forming a shoulder 40 at theupper side of the bottom wall36.

Disposed in the lower portion of the chamber 22 and passing downwardlyout through the bore 38 is a shank portion 42. The shank portion 42includes an enlarged shoulder 49 to limit the bore 33. The lower end ofthe shank portion 42 -is provided with a square cross-sectional socket46 in which is received a complementary-shaped upper end portion 48 of ashank 50. The-upper part 4 8 is retained in the how do by a conventionaltype of ball and socket connection 52.

The shank 50 also includes a square cross-sectional lower part 54.Retained on the lower part ,54 by a second conventional type ballandsocket connection .56 is a removable socket 60, the socket having a .nutor bolt receiving recess 58 in the lower end thereof.

As is best illustraed inFigu're 9, there is formed in the .upper part ofthe shank portion 42 and opening through the upper end thereof aninverted, frusto-conical-shaped recess 62. Seated in the recess 62 is acomplementaryshaped lower part 64 of a male clutch memberfifi. For thepurposes of this invention, the shank portion 42-may have the upper partthereof considered a :female .clutch member. The lower partt64isprovided witha plurality of circumferentially spaced, longitudinallyextending recesses 68 in which are received suitable friction inserts70, as is best illustrated in Figure 4. The friction inserts 70 engagewith the wall of the recess 62 to form a driving connection between themale clutch member 66 and the female clutch member part of the shankportion 42.

In order to normally retain the two halves of the friction type clutchin driving relation, there is disposed within the housing 24 a coilspring 72 which has its upper end seated against a thrust Washer 74carried by the upper part of the upper body 10. The lower part of thecoil spring 72 is disposed in an elongated vertical .bore 76 formed inthe upper part of the male clutch member 66, as is best illustrated inFigure 2. The spring 72 urges the male clutch member 66 down into therecess 62 of the shank portion 42. It is readily apparent that byadjusting the length of the housing 24 by selectively positioning thebodies 10 and 20 with respect to each other, the tension of the spring72- may be varied so as to selectively vary that torque which will causeseparation of the friction inserts 70 from the surfaces of the recess62.

With the exception of a suitable mechanical connection between thehousing 24 and the male clutch member 66, the foregoing elements aregenerally set forth in our prior Patent No. 2,527,517. However, thisparticular arrangement results in the socket 60 being rotated as soon asit is removed from a nut or bolt so that while the torque wrench willoperate effectively, it must be shut off before it can be applied toanother nut or bolt. In order to automatically stop the rotation of thesocket 60 once a predetermined torque has been reached with a nut orbolt disposed in the socket 60, there is provided a cam type clutchbetween the male clutch member 66 and the housing 24.

Referring now to Figure of the drawing, it will be seen that there isillustrated a coupling member which is referred to in general by thereference numeral 78. The coupling member 78 includes a generallycylindrical portion 80 having an annular flange 82 at the lower endthereof. The cylindrical portion 80 is provided with a plurality ofcircumferentially spaced slots 84 in which are seated keys 86. The keys86 are also seated in longitudinally extending recesses 88 formed in theinner surface of the body so as to permit adjustment of the body 10relative to the connecting member 78. The annular flange 82 of theconnecting member 78 seats upon a shoulder 90 formed in the interior ofthe body 20.

Referring now to Figures 6 and 7 in particular, it will be seen that themale clutch member 66 is provided with external threads 92 at the upperend thereof. Intermeshed with the external threads 92 are internalthreads 94 of an annular connecting member 96. The connecting member 96is of the same general cross-section as the body portion 80 of theconnecting member 78.

Formed on the underside of the connecting member 96 is a first camassembly which is referred to in general by the reference numeral 98.The cam assembly 98 includes a plurality of depending cam members 100which are separated by complementary-shaped recesses 102.

Formed on the upper end of the body portion 80 of the connecting member78 is a second cam assembly which is referred to in general by thereference numeral 104. The second cam assembly 104 is complementary tothe first cam assembly 98 and includes a plurality of upwardlyprojecting cam members 106 which are disposed in circumferentiallyspaced relation and which are separated by complementary-shaped recesses108.

-When the Wrench is in its normal operating position, the male clutchmember 66 is held in its down position by the spring 72. This results inthe connecting member 96 being retained in its down position and thecams 100 thereof intermeshed and interlocked with the cams 106 of thecam assembly 104. Therefore, the socket 60 is rotated through a suitableelectric motor and chuck (not shown) to which the shank 16 is connected.The shank 16 in turn results in the rotation of the housing 24. The body10 of the housing 24 is connected to the connecting member 78 to effectrotation thereof. The connecting member 78 rotates the connecting member96 which in turn rotates the male clutch member 66. The male clutchmember 66 rotates the shank portion 42 which, in turn, results in therotation of the socket 60.

When a nut or bolt is being applied and the desired torque is reached,there is a slight slippage between the male clutch member 66 and theshank 42. This results in the turning of the cam assembly 104 relativeto the cam assembly 98 and the resultant riding of the cam assembly 98upon the cam assembly 104. The cam assembly 98 moves the connectingmember 96 upwardly on the connecting member 78 against the downwardurging of the spring 72. When the connecting member 96 rides up on theconnecting member 78, the male clutch member 66 is retained out ofengagement with the surfaces of the recess 62 with the result that theshank 16 is disconnected from the socket 60 and rotation of the socket60 is stopped.

When the socket 60 is pulled off a nut or a bolt, there is a slighttendency for the socket 60 to rotate due to the frictional engagementbetween the shank portion 42 and the body 20. However, this may beeasily overcome by grasping the shank portion 42. The socket 60 may thenbe applied over a next nut or bolt. The wrench is then moved downwardlyto cause slight upward movement of the shank portion 42 with the resultthat the surfaces of the recess 62 are again engaged with the frictionmembers 70. This results in the relative turning of the connectingmember 96 with respect to the connecting members 78 due to the impact ofthe quick making of the connection between the male clutch member 66 andthe female clutch member part of the socket portion 42. The furtheroperation of the torque wrench is then the same as that set forth above.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction shown and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the appended claim.

What is claimed as new is as follows:

In a torque wrench, a tubular housing comprising first and second hollowbodies disposed in telescoped interlocked relation, a driving shanksecured to said first body for rotating said housing, a driven toolreceiving shank rotatably journaled in said second body and projectingtherefrom in axial alignment with said driving shank, said driven toolreceiving shank having an upper end disposed within said housing, anupwardly opening frustoconical recess in the upper part of said driventool receiving shank and opening through said upper end thereof, a maleclutch member, said male clutch member having a frusto-conical lowerportion generally complementary to said frusto-conical recess, frictionelements carried by said male clutch member lower portion and seated insaid frusto-conical recess, said friction element engaging that part ofsaid driven tool.receiving shank defining said recess to form areleasable driving connection between said male clutch member and saiddriven tool receiving shank member, said male clutch member having atubular upper portion terminating in an open upper end, a springdisposed within said tubular upper portion and projecting through saidopen upper end thereof into engagement with said first body, said springbeing in a compressed state and normally urging said friction elementsinto driving engagement with said driven tool receiving shank, a tubularconnector seated in said housing against downward movement, an interlockconnection between said housing and said tubular connector connectingtogether the two for rotation together, said male clutch member beingjournaled in said tubular connector and projecting thereabove, saidtubular connector having an upper end in the form of circumferentiallyspaced alternating projections and depressions connected together byupwardly sloping cam surfaces, a connecting member secured to said maleclutch member adjacent said upper end thereof for rotation therewith,said connecting member overly ing said upper end of said tubularconnection and having a lower part in the form of circumferentiallyspaced downwardly facing alternating projections and depressionsconnected together by downwardly sloping cam surfaces, said projectionsof said tubular connector being complementary to and normally seated insaid depressions of said connecting member and said projections of saidcon- 15 meeting member being complementary to and normally seated insaid depressions of said tubular connector to releasably interlock saidconnecting member with said tubular connector, said upwardly sloping camsurfaces being engaged with said downwardly sloping cam surfaces wherebyrotation between said male clutch member and said housing results in theriding of said connecting mem her up on said tubular connector againstthe resistance of said spring and the movement of said male clutchmember and said fraction inserts out of engagement with said driven toolreceiving shank to release said driven tool receiving shank fromrotation with said housing.

